Precision Nitrogen and Water Management for Enhancing Efficiency and Productivity in Irrigated Maize
Nitrogen and water continue to be the most limiting factors for profitable maize production in the western Great Plains. The objective of this research was to determine the most productive and efficient nitrogen and water management strategies for irrigated maize. This study was conducted in 2016 at Colorado State University’s Agricultural Research Development and Educational Center, in Fort Collins, Colorado. The experiment included a completely randomized block design with five treatments per block. The treatment strips were planted across the entire length of the field in the East to West direction such that the treatment strips traversed over each management zone (low, medium, and high zones). Five N rates of 0, 56, 112, 168, 224 kg ha-1 using 32% Urea Ammonium Nitrate were applied at the V8 crop growth stage. Three rates of irrigation applied at 80, 100, and 120 % of evapo-transpiration were applied throughout the crop growing season by employing weather and soil data that is readily available online, to model crop ET and plant available water in the soil. A significant (P<0.1) and positive grain yield response to increasing levels of N across all site-specific management zones was observed. Likewise, a significant effect of irrigation (P<0.1) was observed across the field and within zones. The four nitrogen management strategies evaluated in this study did have a significant effect on the mean grain yield and nitrogen use efficiency (P<0.1).